Electromagnetic apparatus



Feb. 10, 9 T. J. OMEARA ET ML 9 3 ELECTROMAGNETIC APPARATUS Filed Oct 29, 1929 iNVENTORJ v 77 JT 0 'Mcara, BY v. C. Shaw,

Q'iflW WM ATTORNEY steel Feb. 10, 1931 *iiniTEo STATES PATENT OFFICE MOTH" J, OMEARA, OF PITTSBURGH, AND NOBLE C. SHAW, OF SWISSVALE, PENN- ANIA, AESIGNORS TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISS- iililhifi, IPENNSYLVANIA, A. CORPORATION OF PENNSYLVANIA ELECTROMAGNETIC APPARATUS Application filed October 29, 1929.

Our invention relates to electromagnetic apparatus of the type comprising an electromagnet and an armature coactmg therew th in. the usual manner. One feature of our 1n Tention is the provision, in combination with J ap aratus of this character, of a permanent net co-acting with the electromagnet and armature in such manner as to affect the is required for the armature to release when the electromagnet becomes de-eneri i/eds I i 7s wili describe one form of apparatus hodying our invention, and will then point the novel feautres thereof in claims.

e accompanying drawing is a view showing one form of electromagnetic apus embodying our invention. eferring to the drawing, the reference J E esignates an electromagnet of ype, comprising two parallel cores it and iQ COl\1)8Cted by a back strap 12, which. cores terminate in pole pieces ll and ll, respectively. The cores are provided with the usual energizing winding 14:. Coacting with the electromagnet E in the nsual manner through air gaps 15 and 15 is an .are A pivotally mounted onttrunnions ated diagrammatically by the axial lines whereby the armature may swing toward and away from the pole pieces 11 and 11.

The reference character P designates a permanent magnet having its poles located in lation with the two pole pieces 11 and pectively, of the electromagnet E. shown in the drawing, the adjacent poles of the electromagnet and the permaiient magnet are unlike, that is, the south hole 53 of permanent magnet P is located adacent the north pole N of the electromagnet i and the north pole N of the permanent is iocated adjacent the south pole the electromagnet. It follows that the electroinagnet E is energized, the pen" mz'ignet opposes the electromagnet magnetic flux through the armaaps l5 and 15 and the armature 'n the winding 1 of the electromag becomes die-energized, some of the ie flux in the electromagnet E and tare A. will persist in the direction Serial No. 403,214.

in which it was originally set up by the electromagnet, but the tendency of this magnetism to persist and hold the armature in the closed position will be opposed by counter directional flux from the permanent magnet through the pole pieces 11 and 11, air gaps 15 and 15 and the armature, so that the armature will release more quickly than if the permanent magnet were not present. 3

We will now assume that the permanent magnet P is turned around so that the adjacent poles of the two magnets are alike. The permanent magnet will-then assist the electromagnet in creating magnetic flux through the armature air gaps 15 and 15 and the armature A. Then when the winding 14 becomes de-energized, the permanent magnet will tend to maintain the armature in its closed position because the flux from the permanent magnet through the pole pieces 11 and'11,the'

will delay the release of the armature beyond the normal period required for the release if the permanent magnet were not resent. It is, of course, understood that t e permanent magnet and the air gaps separating this magnet from the elec-tromagnet poles and armature, must be so proportioned that the armature will release before the flux in the relay cores and armature originally set up by current in winding 14, reaches its minimum value.

Apparatus embodying our invention is particularly well adapted for, though in no ivay limited to, use in connection with direct current relays of the type used in railway signalmg.

Although we have herein shown and described only one form of electromagnetic apparatus embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

1. In combination, an electromagnet, an

armature co-acting therewith, and a permanent magnet having its poles closely associated with the two poles respectively of said i electromagnet, whereby the release of said armature is expedited or delayed according as adjacent poles of the electromagnet and permanent magnet are unlike or like.

2. In combination, an electromagnet comprising the usual cores terminating in pole pieces, an armature co-acting in the usual manner with said electroniagnet, and a permanent magnet having one of its poles located close to one pole piece of said electromagnet and its other pole located close to the other 15 pole piece of the electromagnet.

In testimony whereof we affix our signatures.

THOMAS J. OMEARA. NOBLE C. SHAW. 

